There are known solutions, where acquired images are time-synchronized via special hardware (e.g. U.S. Pat. No. 8,654,251B and U.S. Pat. No. 8,717,422B, G. Litos et al, “Synchronous Image Acquisition based on Network Synchronization” etc). Such solutions are sophisticated and costly to be implemented, as requiring complex hardware and wiring. In addition, the network synchronization in computer systems has significant latencies and uncertainties, in the order of tens of milliseconds.
There are also known solutions, where frames of the acquired image streams are synchronized or related to each other by monitoring, and matching (in the algorithm) the moving objects (e.g. feature points) by various cameras, in parallel. The drawback of such solutions is that the frames are not still connected to the (absolute) time-base, so also making it impossible to track the positions of the image frames. In addition, such algorithms are computationally sophisticated and time consuming, as the objects (feature points) are located at unknown co-ordinates and have unknown and unpredictable features. In addition, results of such approach depend much on the illumination of the scene conditions.
Also, there are known multi-camera solutions, where the cameras are synchronized to each other by using of the binary modulated (by special pattern) light source (e.g. LED), being visible in the image frames, e.g. as described in US2011035174A and Japanese patent specification JP5213045B2.
The closest solution known in the art is described in the paper (Qi Zhao, Y. Q. Chen, “High-precision synchronization of video cameras using a single binary light source”, J. Electron. Imaging. 18(4), 040501, Oct. 20, 2009), where the frames are matched to each other by using of the modulated binary light source and by decoding this binary modulated light intensity in the post-processing stage. The drawback of this and other solutions is that the frames are still not related to the (absolute) time base, so also making it impossible to track and map the positions (co-ordinates) of the capture of image frames. Thus, there is a need for new improved method and device for precise time-stamping of the image frames.